Electronic device for auto focusing function and operating method thereof

1. An electronic device comprising:

a camera module including a focus lens;

a display; and

a processor,

wherein the processor is configured to:

control the camera module to obtain a first image at a first position of the focus lens;

control the display to output the first image;

control the camera module to obtain a second image at a second position of the focus lens while the first image is being output;

calculate a defocus amount of the focus lens at the second position based on the first image and the second image, wherein the output of the first image is maintained at least until the defocus amount is calculated;

detect an on-focus region based on the calculated defocus amount;

determine a movement direction of the focus lens with respect to the on-focus region;

control the camera module to obtain a third image at a third position of the focus lens, wherein the focus lens is moved to the third position based on the determined movement direction; and

control the display to output the third image,

wherein whether to maintain the output of the first image after the calculation of the defocus amount is determined based on the movement direction of the focus lens.

2. The electronic device of claim 1 , wherein the processor is further configured to:

control the display to replace the first image with the third image based on the defocus amount.

3. The electronic device of claim 2 , wherein the processor is further configured to control the display to output the second image before the first image is replaced with the third image.

4. The electronic device of claim 3 , wherein, when the second position is in a first direction in proximity to the on-focus region with respect to the first position, the processor is further configured to control the display to output the second image before the first image is replaced with the third image.

5. The electronic device of claim 4 , wherein, when the focus lens is moved over a reference distance from the second position in the first direction, the processor is further configured to control the display to output the second image before the first image is replaced with the third image.

6. The electronic device of claim 5 , wherein, when the focus lens is moved less than the reference distance from the second position in the first direction, the processor is further configured to control the display to continue outputting the first image before the first image is replaced with the third image.

7. The electronic device of claim 3 , wherein, when the second position is in a second direction that moves away from the on-focus region with respect to the first position, the processor is further configured to control the display to continue outputting the first image before the first image is replaced with the third image.

8. The electronic device of claim 2 , wherein the processor is further configured to detect the on-focus region based on a contrast of the third image.

9. The electronic device of claim 1 , wherein the processor is further configured to calculate the defocus amount based on a blur between the first image and the second image.

10. A method of operating an electronic device, the method comprising:

obtaining a first image at a first position of a focus lens of a camera module of the electronic device;

outputting the first image through a display of the electronic device;

obtaining a second image at a second position of the focus lens while the first image is being output;

calculating a defocus amount of the focus lens at the second position based on the first image and the second image, wherein the outputting of the first image is maintained at least until the defocus amount is calculated;

detecting an on-focus region based on the calculated defocus amount;

determining a movement direction of the focus lens with respect to the on-focus region;

obtaining a third image at a third position of the focus lens, wherein the focus lens is moved to the third position based on the determined movement direction; and

outputting the third image though the display,

wherein whether to maintain the outputting of the first image after the calculating of the defocus amount is determined based on the movement direction of the focus lens.

11. The method of claim 10 , wherein detecting the on-focus region comprises:

replacing the first image with the third image.

12. The method of claim 11 , wherein detecting the on-focus region further comprises outputting the second image before the first image is replaced with the third image.

13. The method of claim 12 , wherein detecting the on-focus region comprises outputting the second image before the first image is replaced with the third image when the second position is in a first direction that is in proximity to the on-focus region with respect to the first position.

14. The method of claim 13 , wherein detecting the on-focus region comprises outputting the second image before the first image is replaced with the third image when the focus lens is moved over a reference distance from the second position in the first direction.

15. The method of claim 14 , wherein detecting the on-focus region comprises continuing to output the first image before the first image is replaced with the third image when the focus lens is moved less than the reference distance from the second position in the first direction.

16. The method of claim 12 , wherein detecting the on-focus region comprises continuing to output the first image before the first image is replaced with the third image when the second position exists in a second direction that moves away from the on-focus region with respect to the first position.

17. The method of claim 11 , wherein detecting the on-focus region comprises calculating a contrast of the third image.

18. The method of claim 10 , wherein calculating the defocus amount comprises calculating a blur between the first image and the second image.